Tunable micro-lens arrays

Abstract

An apparatus includes a planar substrate and an array of substantially transparent spherical micro-lenses forming a pattern. The pattern has an internal two-dimensional lattice symmetry on the planar substrate. Each micro-lens includes a convex bulge or a concave depression in a surface of the planar substrate. The micro-lenses and substrate include hydrogel that swells and contracts in a manner that is responsive to an environmental condition.

1. An apparatus, comprising:
 a planar substrate; and 
 an array of substantially transparent spherical micro-lenses on the substrate, the micro-lenses forming a pattern, the pattern having an internal two-dimensional lattice symmetry on the planar substrate; and 
 wherein each micro-lens comprises one of a convex bulge in a surface of the planar substrate and concave depression in a surface of the planar substrate; and 
 wherein the micro-lenses and substrate comprise hydrogel that significantly swells and contracts in a manner responsive to an environmental condition. 
 
   
   
     2. The apparatus of  claim 1 , wherein each micro-lens has one spherical surface and one flat surface, the flat surface being on an opposite side of the substrate as the spherical surface. 
   
   
     3. The apparatus of  claim 1 , further comprising:
 a second planar substrate that is substantially transparent; and 
 wherein the array is constrained to rest on the second substrate in a manner than enables the array to swell and contract. 
 
   
   
     4. The apparatus of  claim 1 , wherein a center-to-center spacing between the micro-lenses of the array is less than about 500 microns. 
   
   
     5. The apparatus of  claim 1 , further comprising:
 a spatially segmented light intensity detector positioned to intercept light spots produced by the micro-lenses; and 
 a data processor configured to receive intensity and position data from the light intensity detector.